Rotary piston machine



Oct. 24, 1967 A. FISCHER ROTARY PISTON MACHINE Filed Jan. 23, 1967 4Sheets-Sheet 1 jOct. 24, 1967 AQFISCHER ROTARY PISTON MACHINE 4Sheets-Sheet 2 Filed Jan. 23, 1967 A- FISCHER ROTARY PISTON MACHINE Oct.24, 1967 4 Sheets-Sheet 5 Filed Jan. 23, 1967 \m J x Em QM m m i mm 37./ 7 mm mm, km Qm mm mm m6? Oct. 24, 1967 A. FISCHER 3,348,494

ROTARY PISTON-MACHINE Filed Jan. 23, 1967 4 Sheets-Sheet 4 United StatesPatent 3,348,494 ROTARY PISTON MACHIN Arno Fischer, Rottenbuch, UpperBavaria, Ammermuhle,

Germany, assignor to Halbergerhutte G.m.b.H., Brebach, Germany, acorporation of Germany Filed Jan. 23, 1967, Ser. No. 611,133 13 Claims.(Cl. 103-136) ABSTRACT OF THE DISCLOSURE A rotary piston machine of theparallel axes type includes a working chamber within which is at leastone piston consisting of a piston hub and a tubular vane or slidemember, said slide member lying against a running surface of theperipheral wall of the working chamber.

The invention relates to a rotary piston machine, particularly aparallel axis rotary piston machine having a peripheral wall which isprovided with running surfaces, which possess zones near the axis andzones remote from the axis, and having a piston consisting of a pistonhub and at least one slide member, wherein in each case a workingchamber is formed between two zones near the axis. The inventionconsists in that in the working chamber bounded by running surfaces ofthe peripheral wall, the piston and the side parts at least one slidemember lies against a running surface on the peripheral wall, while theside parts are joined fast to the piston, and the slide members have theform of open-ended tubes and are guided in the side parts.

According to another aspect of the invention, the principle of theconstruction of the working chambers and of the slide members may beapplied to crossed axis rotary piston machines having running surfacesextending at any desired angle to the axis of rotation of the machine.

Another construction according to the present invention provides for theaxis of the slide members to extend at an angle to the radial plane.

According to the invention the tubular slide members may be soconstructed that they are reinforced, for example by bridges or ribs, ontheir interior. In some cases it is advantageous for the slide membersto be composed of at least two tubes disposed side by side.

One embodiment of the invention, moreover, consists in that the tubularslide member has at its end a seal associated with the running surface.

A further advantageous form of construction also consists in that theworking chambers in their succession form an annular chamber subdividedby partitions, the width of the tubesor, in the case of circular pistontubes, their diameter-being greater than the respective dimension of theannular chamber measured in a plane laid through the axis of the machineand the axis of the tube, in such a manner that in the region in whichthe tubes cooperate with the peripheral wall carrying the partitions thetubes are adapted to said wall in a formlocking manner.

According to the invention, provision is also made for each slide memberto be slidable under the control of a self-contained control cam adaptedto the path of the running surface by guide elements connected to it andcooperating with the control cam, the latter and the guide elementsbeing situated outside the working chambers. Moreover, control may alsobe effected by means of other kinematic elements. The control may alsobe so arranged that the control cam is formed as a curved slot in whichrunning rollers engage, which rollers are mounted on the end of links'rockably connected to the slide members. The control cam may beconstructed as a curved slot only in the region of the zones of therunning surface 3,348,494 Patented Oct. 24, 1967 ice which lie near theaxis, While elsewhere it has the form of an outwardly curved path.

In some cases it is advantageous for the control cam to be made elasticin some regions of the running surface.

Another form of construction according to the invention provides for thesliding path of the slide members to be limited by stops in the case ofguide elements which do not cooperate positively.

According to the invention a machine of this type may also be soarranged that at least two individual machines are disposed allochirallyand combined to form a constructional unit which is a single annularchamber, and are operated after the style of a boxer engine havingopposed pistons. A plurality of such machines may also be disposed on acommon shaft, connecting apertures being provided between the axiallyadjoining tubular slide members.

In this connection it should be observed that the resulting free spaceson the working rear side of the tubular slide members may also be shapedas working chambers. An annular chamber formed in this manner issubdivided by mutually offset partitions.

Machines of this type could hitherto be constructed only for limitedpressures of the operating or working medium. The utilization of high,and very high, pressures entails various problems. On the one hand theslide members must be very sturdy in order to have sufiicient strengthto withstand the forces present at high pressures. If, however, theslide members are made of solid construction it has been found thatafter passing below the partitions separating the working chambers theslide member-s arein each case moved into the working chamber subjectedto the pressure of the working medium. Thus, a solid slide memberdisplaces working medium and at the same time is subjected to a forcecorresponding to its cross-section and to the pressure of the workingmedium, this force acting against its movement. In the case of theapplication of high and very high pressures these forces become verygreat, which circumstance has a particularly disadvantageous effectprecisely because the application of high and very high pressures leadsto small dimensions of the machine, which thus permits only limiteddimensions for the parts necessary for moving the slide members. Whenhigh and very high pressures are applied, moreover, particularlystringent requirements are imposed on the seal between the pressure sideand the unloaded side of the slide members.

A principal object of the invention is to provide a construction of arotary piston machine (e.g., pump, or motor) of the above described typewhich complies with all recited requirements.

The invention achieves this object through the fact that the side partsare joined fast to the piston, and the slide members are guided in theside parts, and that the slide members are tubular and have open ends.Through this tubular construction the slide members are given.

serted into the working chamber the medium displaced by the slide membercan flow off through the slide member and penetrate into the space freedby the slide member through its sliding movement. At both ends of thetube the pressure is, therefore, the same during the movement of theslide members, so that the moving forces are extremely small. Theworking medium is also not displaced into the working chamber by theslide member, but can flow off towards the rear end of the latter Thetubular construction of the slide members provides the additionaladvantage that, despite their great power of resistance, they need haveonly a relatively small weight. Moreover, at the point of contactbetween the slide members and the side parts a relatively great sealinglength is achieved, which circumstance provides a considerable advantageparticularly at the high and very high pressures applied.

A parallel axis rotary piston machine is already known in which the sideparts are joined fast to the piston and the slide members are guided inthe side parts. In this known machine, however, the recesses formed inthe side wall ares extended beyond the working chamber, so that fillersmounted at the sides of the slide members are necessary. In addition,the slide members in this known machine are constructed as simple soliddiscs and not as open tubes.

It is advantageous for the number of pistons in the motor or pump toamount to twice or a multiple of the number of partitions, because athigh and very high pressures of the working medium this ensures that theforces occurring during the rotation of the rotor of the workingmachine, acting on the axis of rotation, and originating from thepressure of the working medium, cancel one another. In an asymmetricallyconstructed machine, on the other hand, very high rotating or evenjumping radial forces would act on the axis or mounting of the rotor ofthe machine, and would jeopardize the practicability of a machine ofthis type.

The control cam used in accordance with the invention in the presentmachine ensures that the slide members are moved out of the region ofthe working chambers in the area of the running surface zones situatednear the axis, in order to prevent the slide members from running ontosaid zones situated near the axis. In order to make full use of theavailable volume of the Working chambers, the radial movement of theslide members is effected in a relatively small angular region at theend of the working chambers.

Where in a known rotary piston engine slide members are joined topush-rods which are provided with running rollers at the end facing theaxis, these lie against a central stationary cam under the action ofcompression springs. Corresponding to the path of the running surfacethe cam also has Zones situated near the axis and Zones remote from theaxis. The smaller the angular region selected for the transition from azone near the axis to a zone remote from the axis, or vice versa, thesteeper is the rise of the control cam in this transition region and, independence thereon, the radial acceleration of the control slide member.The permissible acceleration of the slide members, and also thenecessary transition curves in the path of the control cam, impose alower limit on the angular region of the transition movement and anupper limit on the speed of the rotating piston. If a rotary pistonmachine of this type is used at high and very high pressures, thedimensions of such machines can be kept very small. However, the smallerthe dimensions of the machine, the greater will be the slopes of thecontrol curve if the displacing movement of the slide members is to beeffected within a determined sector. Through the special construction ofthe control cam according to the invention it has now been made possiblefor the machine as a whole to be given very small dimensions withoutexceeding the permissible acceleration of the slide members.

In those cases where in the machines according to the invention theannular chamber which is formed by the successive working chambers iscut to its full depth in the constructional body carrying the pistons,and if at the same time use is made of pistons which are constructed astubes open at both ends, then during the rotation said pistons will beconstrained to move rhythmically in the direction of their axis out of arespective chamber, which is closed at the rear, into the annularchamber and out of the latter again. This is particularly when the axisof the tubes extends parallel to the axis of rotation of the machine,because if in such a case the constructional body carrying thepartitions were to be connected at its end face to the constructionalbody carrying the pistons the pressure of the working medium would drivethe two constructional bodies apart in the axial direction. Through thearrangement according to the invention, in which the constructional bodycarrying the partitions closes the annular chamber cylindrically, thisis avoided.

Further features of the invention will be seen from the followingdescription of exemplified embodiments, in conjunction with thedrawings, and the claims.

In the accompanying diagrammatical drawings:

FIGURE 1 is a radial section through the center of the annular workingchamber of the machine;

FIGURE 2 is an axial section through the machine illustrated in FIGURE1;

FIGURE 3 is a cross-section through the embedding of a circular slidemember in the side parts of the piston;

FIGURE 4 is a cross-section through a circular slide member which isreinforced by an internal rib;

FIGURE 5 is a cross-section of a slide member c0nsisting of two tubesdisposed side by side;

FIGURE 6 is an axial section through a machine in which the axes of thetubes extend parallel to the axis of rotation of the machine;

FIGURE 7 is an axial section through a machine in which the workingchambers forming an annular space are cut in the rotating part;

FIGURE 8 is a portion of the radial section on the line AA in FIGURE 7;and

FIGURE 9 illustrates an example of the assembly of two individualmachines which are disposed in mirror image symmetry (i.e.,allochirally) to one another and are combined to form a constructionalunit.

FIGURES 1 to 3 illustrate a hydraulic motor in which a stator 1 ismounted fast or prevented from rotating by means of the stops or cams 2.Together with the piston hub 3, the stator 1 forms the annular space 4which is subdivided by the partitions 5 mounted on the stator 1 and bythe vane or slide members 6 carried by the piston hub 3. Two partitions5 are provided, with each of which there are associated one inlet 7 andone outlet 8 for the working medium of the machine. The annular spaceaccordingly has two working chambers. A total of four slide members areprovided, whereby the effect is achieved that two working chambers arealways acting. The number of pistons also amounts to twice the number ofpartitions, whereby the effect is achieved that the radial stresses arealways mutually cancelled by the pressure of the working medium in thetwo working chambers. The slide members 6 are constituted by round tubeswhich are open at both ends.

The invention is, however, not restricted to the use of round tubes butit is also possible to use tubes having a square or rectangularcross-section.

The axis of the slide members 6 extends in the radial direction, and onthe rotation of the piston 3 the slide members 6 are moved in the samedirection out of the chambers '9 into the annular space 4 and out of thelatter again.

The chamber 9 is closed at its rear, but it is also conceivable for twochambers of the machine which always work similarly to be connectedtogether in each case; that is to say, in the exemplified embodimentillustrated in FIGURE 1 two chambers 9 lying opposite one another ineach case. It can be seen from FIGURES 2 and 3 that the diameter of theslide members 6 is greater than the width 25 of the annular space 4. Theincreased sealing length corresponding to the dimension of the arc 2424is thereby obtained for the seal between the spaces on both sides of theslide members 6. With the same width 25 of the annular space 4 and thediameter of the slide members, there would be only linear contactbetween the latter and the side walls of the annular space; that is tosay, there would be only very short sealing length.

A greater length is also provided in the peripheral direction by theslide members for the seal between their front end face and the innerperipheral surface of the stator 1 than in the case of flat slidemembers of conventional construction.

The minimum sealing length existing here corresponds to twice the wallthickness of the slide member. The concept of providing the slidemembers with thick walls because of stressing by the high pressures ofthe working medium accordingly has at the same time the effect ofimproving the seal.

It is possibleand is, moreover, in accordance with the sense of theinventionto provide on the end face of the slide member, whichcooperates with the inner peripheral wall surface of the stator 1special material assisting the sealing action and/or sliding properties,such as for example oil-proof rubber, bearing metals, or the like, whichmaterial may also be inserted-into the slide member as a concentricring.

From FIGURE 1, moreover, it can be seen that the length of thepartitions 5, measured in the direction of movement, is greater at theirpoint adjoining the bottom of the annular space than the diameter of theslide members. The effect thereby is achieved that when the slidemembers 6 .pass beneath the .partitions 5, as is shown by the slidemembers having horizontally directed axes, the inwardly directed endface of the partition 5 cooperates with the bottom peripheral surface ofthe annular space so as to provide a seal during the entire process ofpassing therebeneath. i

On the rotation of the piston hub the slide members 6 are moved out ofthe chambers 9 into the annular space 4 and out of the chambers 9 intothe annular space 4 and out of the latter again. As the exampleillustrated shows, this is effected mechanically by means of the roller11 joined by the member to the piston slide valve 6 and of the runningsurface 12. The movement could also be effected hydraulically or the'mechanical moving device could also be provided with hydraulicassistance.

In this arrapgementthe part 13 of the running surface 12, as illustratedfor example for the upper half of the running surface in FIGURE 1, maybe constructed elastically by meanspfi the underlayer 14 "of rubber orthe like or be sprungby means of the springs 15. The effect is therebyachieved that thepiston slide valves 6 lie against the annular spaceperipheral surface of the stator 1 with pressure corresponding to thespringing. 1 The movement of advance of the piston slide valves 6 intothe annular space-4'may be limited by stops. The tips 16 of the slideand sealin-g'rings 17 disposed on the stator 1 and illustrated in FIGURE2, or the boundary 18 of the recess 19 in the piston hub 3 may serve asstops for the driver bolt 20. Y Both stops may also be effective at thesame time. This 1s of particular importance in the present case because,as already mentioned, very considerable forces may act on she stopsthrough the high pressures of the working merum.

Whereas on the left-hand side of FIGURE 2 sealing rings 17, which at thesame time also serve to mount the piston hub 3, are illustrated for theseals between the stator 1 and the piston hub 3, this sealing may alsobe ef fected in any other conceivable manner. On the right-hand side ofFIGURE 2, annular bead seals 21 are accordingly illustrated. The pistonhub 3 may likewise be mounted on the stator 1 in any other conceivablemanner. From FIG- URES 1 and 2 it can be seen that the running surface12 is disposed as far to the outside as possible, so that there arerelatively gentle gradients for the curves.

In FIGURE 2 the running surface 12 is disposed at the top and the driveflange 22 for the piston hub 3 at the bottom. The running surfaceaccordingly extends on the opposite side of the annular space 4 to thedrive side, which results in particularly simple constructionaldimensions. It would also be conceivable to provide running surfaces 12one on each side of the annular space 4.

FIGURE 4 shows a cross-section through a circular slide member which isreinforced by a bridge extending in the direction of the main forceaxis.

This may be of importance because of the high pressures expected,particularly when the slide members are constructed with thin walls inorder to reduce their weight, which is advantageous in high speedmachines. The end faces of the slide members will in this case also bemade with thick walls in order to obtain adequate sealing lengths.

. FIGURE 5 shows a cross-section through a slide member which iscomposed of two tubes disposed side by side in the direction of thewidth of the working chamber. The dimensions of the slide member in theperipheral direction are thereby shortened, which circumstance isimportant when it is required to subdivide the annular space into thelargest possible number of Working chambers. The construction of theslide member from two tubes provides the advantage that in this casealso, as in the case of the slide member consisting of a circular tube,the spaces in which the slide members move radially in the piston hub 3can be produced by simply boring out the piston hub 3. It can likewisebe seen in FIGURE 5 that the slide member composed of two tubes alsoengages on both sides in the side walls of the annular space, wherebythe greatest possible sealing length is obtained. -As compared with theslide member consisting of only one tube, the respective arc length isnaturally shorter. It is, however, conceivable to improve the sealing bymeans of additional sealing devices 23. Such measures could also betaken in the case of the slide member consisting of one tube.

FIGURE 6 illustrates an example of construction of a machine accordingto the invention, in which the axes of the piston tubes extend parallelto the axis of rotation of the machine. At the same timeit constitutesan example of the case where two ormore individual machines arestructurally combined to form a machine unit. In this case also thechambers 9 of the two pistons 6, which work similarly to one another,are joined together, which is,

achieved by means of the bore 26.

Another form of construction is illustrated URES 7 and 8, wherein thestationary stator 27 is providedwith partitions 28. On both sides of thepartitions 28 there are disposed the inlets 29 and outlets 30 for'theworking medium. An annular chamber 32 is entirely out out. of therotating part 31 of the machine. It is closed cylindrically by thestator 27. Axially movable tubular pistons 33 are inserted in therotating part 31. On the rotation of the rotor 31 the pistons'33 aremoved rhythmi-' cally out of the chamber 37 into the annular space 32and out of the latter again by means of bolts 34 and rollers 35 throughslotted links 36. In this way the path for the partitions 28 isrhythmically freed by constraint for the passage of the annular space32.

According to one aspect of the invention, the width 40 of the pistontubes 33, measured in a plane passed through the axis of the machine andthe axis of the piston, is greater than the respective dimension of theannular space, in this case the radial height 41. The effect is therebyachieved that between the tubular piston and the respective walls of theannular space there is not only linear guidance but also a great sealinglength, viewed in the peripheral direction.

' As can be seen from FIGURE 8, the partitions 28 are made so thick thatby the diameter 42 they. cover the passage apertures 38 which areprovided in the wall of the annular space and through which the pistontube is moved into and out of the annular space. The recess 39 providedin the rotor 31 for the movement of the piston tube is' also covered,since its length 43 in the peripheral direction is substantially smallerthan the thickness of the partition 28 measured in the peripheraldirection.

FIGURE 9 illustrates an embodiment in which two single machines aredisposed in an allochiral arrangement in relation to one another and aregrouped together to form a structural unit in such a manner that theyform a in FIG-.

common annular space. The annular space 32 is in this case disposed inthe center of the machine. From both sides the pistons 33 are moved inopposite directions into and out of the annular space 32 after the styleof a boxer engine. The pistons 33 encounter one another in the center ofthe annular space 32, and suitable means are adopted to provide a sealat the point of contact of the two pistons during the time in which theyare in contact. As compared with the arrangement illustrated in FIGURE 6the solution illustrated in FIGURE 9 provides the particular advantagethat the distance which the pistons have t travel rhythmically is onlyhalf as great.

I claim:

1. A fluid displacement device, comprising a stator;

a rotor coaxially mounted within the stator and forming at least twoworking chambers between stator and rotor;

vane members associated with said working chambers and mounted in saidrotor for movement into and out of said Working chambers;

the stator having radially or axially staggered peripheral runningsurfaces engageable by said vane members;

each vane member having the form of an open-ended tube one end of whichengages said running surfaces;

the working chambers having side walls which are formed by integralflanges on the rotor between which flanges said tubular vane members areguided.

2. A device as defined in claim 1 in which the vane members are disposedin the rotor with their axes parallel to the axis of the rotor.

3. A device as defined in claim 1 in which the vane members are disposedin the rotor with their axes at an angle to the axis of the rotor.

4. A device as defined in claim 1 in which the running surfaces extendat any inclination to theaxis of the rotor.

5. A device as defined in claim 1 in which the tubular vane member isinternally reinforced by a Web or rib.

6. A device as defined in claim 1 in which the vane member comprises atleast two tubes disposed in juxtaposed relationship.

7. A device as defined in claim 1 in which the tubular vane member has aseal at that end thereof facing said running surfaces.

8. A device as defined in claim 1 in which the working chambers insuccession form an annular space which is subdivided by partitions,while the cross-sectional dimension of the tubular vane members isgreater than the respective dimension of the annular space, measured ina plane extending through the axis of the device and the axis of thevane member, whereby the vane members are adapted in a form-lockingmanner to the peripheral wall carrying the partitions in the region inwhich they cooperate with said peripheral wall.

9. A device as defined in claim 1 in which each tubular vane member isslidable in accordance with a self-contained control cam, adapted to thepath of the running surface by means of guide elements joined to it andcooperating with the control cam, the control cam and the guide elementsbeing situated outside the working chambers.

10. A device as defined in claim 9 in which said control cam is ofelastic construction in individual regions on the running surfaces.

11. A device as defined in claim 1 in which the path of the tubular vanemembers is limited by stops in the case of guide elements notcooperating in a form-locking manner.

12. A device as defined in claim 7 in which at least two individualdevices are allochirally disposed and are combined to form a commonannular chamber and are operated with oppositely acting tubular vanemembers in the manner of a boxer engine.

13. A device as defined in claim 1 in which a plurality of the devicesare disposed on a common shaft, connecting apertures being providedbetween the axially adjoining tubular vane members.

References Cited UNITED STATES PATENTS 1,051,360 1/1913 Wisdom 1031361,603,437 10/1926 Wingquist 103136 1,974,122 9/1934 Phillips 103--1362,125,988 8/1938 Broman 103136 2,356,916 8/1944 Brewster 1031362,394,120 2/1946 Tucker 103136 2,957,429 10/ 1960 Fisk 103139 2,977,8894/1961 Fisk 103139 2,980,030 4/ 1961 Couturier 91-126 3,154,293 10/1964Matson 103136 DONLEY I. STOCKING, Primary Examiner.

WILBUR I. GOODLIN, Examiner.

1. A FLUID DISPLACEMENT DEVICE, COMPRISING A STATOR; A ROTOR COAXIALLYMOUNTED WITHIN THE STATOR AND FORMING AT LEAST TWO WORKING CHAMBERSBETWEEN STATOR AND ROTOR; VANE MEMBERS ASSOCIATED WITH SAID WORKINGCHAMBERS AND MOUNTED IN SAID ROTOR FOR MOVEMENT INTO AND OUT OF SAIDWORKING CHAMBERS; THE STATOR HAVING RADIALLY OR AXIALLY STAGGEREDPERIPHERAL RUNNING SURFACES ENGAGEABLE BY SAID VANE MEMBERS; EACH VANEMEMBER HAVING THE FORM OF AN OPEN-ENDED TUBE ONE END OF WHICH ENGAGESSAID RUNNING SURFACES; THE WORKING CHAMBERS HAVING SIDE WALLS WHICH AREFORMED BY INTEGRAL FLANGES ON THE ROTOR BETWEEN WHICH FLANGES SAIDTUBULAR VANE MEMBERS ARE GUIDED.